Chemical Activation of a Single Melamine Molecule via Isomerization Followed by Metalation with a Copper Atom

TL;DR

This study demonstrates how a single melamine molecule can be chemically activated and reacted with a copper atom using scanning probe techniques.

Contribution

The paper introduces a method to activate and metalate a single molecule while measuring the forces and energies involved.

Findings

Melamine adsorbed on Cu(100) can be activated via tautomerization and metalation with a single Cu atom.

Atomic force microscopy identifies the reactive site and transfers a Cu atom to it.

The forces and energies involved in the metalation process are quantified experimentally and supported by DFT calculations.

Abstract

Scanning probe methods have very successfully been used
for inducing
on-surface reactions and imaging with high resolution the reaction
partners at the single-molecule level. However, the entire sequence
of chemically activating an educt, identifying its reactive site,
running a chemical reaction, and quantifying the involved forces and
energies has been missing to date. Here, the organic molecule melamine
adsorbed on Cu(100) serves as a single-molecule model system for activation
via tautomerization and subsequent metalation with a single Cu atom.
An atomic force microscope with a CO-decorated tip probes the most
reactive intramolecular site of the tautomer, while a Cu-terminated
tip transfers a single Cu atom to this site. Following the interaction
between the mutually approached reaction partners up to the verge
of chemical-bond formation enables access to the force and energy
involved in the single-molecule metalation process. Total-energy calculations
from density functional theory support the experimental findings and
illustrate the structure of the reactants.

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